Pneumatic elevator for flour mill stocks



May 26, 1953 G. WATTS 2,639,862

PNEUMATIC ELEVATOR FOR FLOUR MILL STOCKS Filed June 16, 1950 5 Sheets-Sheet 1 I 221/ an i01 May 26, 1953 G'. WAT S ,v 2,639,862

- PNEUMATIC ELEVATOR FOR FLOUR MILL STOCKS Filed June 16, 1950 .s'sneets-sheet 2 May 26, 1953 G. WATTS 2,639,862

PNEUMATIC ELEVATOR FOR FLOUR MILL STOCKS Filed June 16, 1950 5 Sheets-Sheet 5 May 26, 1953 G. WATTS PNEUMATIC ELEVATOR FOR FLOUR MILL STOCKS 5 Sheets-Sheet 4 Filed June 16, 1950 Ma 26, 1953 G WATTS 2,639,862

PNEUMATIC ELEVATOR FOR FLOUR MILL STOCKS Filed June 16, 1950 5 Sheets-Sheet 5 Patented May 26, 1953 UNITED STATES T OFFICE George a head ea Ste m r; En land, assignor to Henry S iinon (I-Ioldi ng's') Ljmited, Cheadle Heath, Stcl 'ioit, England, a

ri pl-i'cationjime 16, 1950;1seria1 No". 168,401: In Great Britain Jiily 8, 1949 18 Ciaiiiis". 1

This invention relates to pneumatic elevators for flour mill stocks (which term includes grain and the products resulting from the milling. of grain) where thc-machine-fromwhich the stock to be elevated is obtained needsan exhaustion action to be applied thereto. The air to be exhausted from the machine may enter the latter throughthe tops or through doors or other in-' lots provided on the machine-.

It is known that whilst the pneumatic system for the purpose indicated has many advantages, itinvotves heavy' power consumption due to the large volume of air which has to be dealt with and the: high velocity which h'asto be imparted to the air, due: to the employment of horizontal pipes with bends, to" prevent choices in the pipe system and to keep thestcck in contact with the surface of i the pipe system mobile".

The object of the present invention: is; to pro= vide an improved pneumaticelevator system: or arrangement in combination with a mill gri-n'd i-n'g machine to be exhausted and which the volume of air necessary to carry the stock dan be materially reduced as can also the velocity of the: air requisite to keep the stockmobile.

The: invention consists in a pneu ma-tic system forfiour mill stock from a machine on machines into which all! is drawn b3? the pneumatic 5375-" term. so' that the machine: is exhausted and-the aerate'clgicomprisingi avertieai or. substan== trally vertical pipe (to the top ofwhich suction spouses intowhichthe stock-- is;- delivered bi gravity at appointalcove the bottom of said pipe, the sa id bottoni being either open or opening-if the suction fans, so to allow" stock to" ran out of the pipe and not block the same whenthe suctidmfailathe top: of the pipe leading to separaters; stools and dust;

'lvia'emvention: fiirther comprises the arr ange= met-l t in which the travellingv with: the: mill stools to the elevating: pipe is separated from-the stock an'd delivered separately into the elevating p'i-pe eith'er above on below the point at which the mill stock en'terssuch pipe.

The: invention further" comprises thearrangement in-wh-ich the sep'arated air enters thebot tom of the: elevating pipe: th-rou-gh atnormall'y closed connection forms the sole elevating air, the said connection: opening: to permit discharge t stock from the; connection when the suction fails.

lheinvention further comprises-- thearrange ment in which a rotary'air sealis provided in-the pipe'deliverihg the mill: stock into the elevatin pipe. v

The invention further comprises the arrangemerit in which one or more elevating pipes through the machine front which stock and; air are withdrawn; the internal base of the machine directing the stools into the elevating pipe or n n v Theinvention further comprises the mangement in which a mechanical conveyor delivers the aerated mill-stock fromthe machine to a feed.

pipe leading? to the vertie'aler substantially ve1=- ti-cal elevating pipe; 7

The invention further comprises the arxgaiigemerit in which a controlvalve situatedinthe pipe for separated i The invention further comprises arrange ment in: whichthebottom open end of the elevating pipe is adjustable in cross sectionalarea torcontrol the volume flow of air into thepipe for stock elevating purposes. I

The invention further eomprisesthearrange ment which the elevating pipe is free from behdsor ledgesfor'about 1-5 test-from the point Where the elevating air is admitted thereto;

The invention further comprises the arrangemeritin which the top of the elevating pipe de= livers tangential-1y into a; cyclone separator having its axis horizontal or substantially so;

Referring to the accompanying explanator;

drawings: H

Fighte 1- a general view ofam elevating systern: for flour products arrangedin one com venient form inaccordance with this invention.

Figures-2 tan-d showvarying dispositions of thedaist separator ofthe system shown in Figuredw Flames" 5 and some views taken at right angles to one another with certain parts cut-away, showing a modification in which the elevating pipes paiss through the machine from'which precincts ar'e'to he el-evaite'da l i'eiires 742'- show va'riol'ismodified arrangw into the roller millthrough suitable inlet means 1 panti-cularlyadustable doors 9- in-to a feed-- spqnt b, which delivers the aerated stock into the e'l'e' vating pipe 0. The latter i's 'p'rerrat a p vertical pipe for a vertical distance of at least 15 feet, in some cases the vertical length may be as much as 100 feet, from its open base cl where air to elevate the stock enters the system. One side e of the elevating pipe below the delivery end of the feed spout b is movable and adjustable in its movement by the screw and nut device f to regulate the area for the inflow of air into the system. 4

There is a medium pressure fan at g which draws the air and stock from the elevating pipe into the cyclone type separator h and delivers the air which is lightly laden with dust from the cyclone h to the separator i which may have textile filters therein. There is a low pressure exhaustion fan at 7' which exhausts the separator i. The stock separated from the air in the cyclone h is discharged through the rotary air seal at k. The solid material separated from the air in the separator i is discharged through a "rotary air seal at m.

The area for the flow of stock from the feed "spout b into the elevating pipe 0 can be varied by the slide valve 12. This valve and the adjustable side e of the elevating pipe can regulate the ratio of elevating air to the air drawn into the pipe 0 along with the stock from the machine al It will be noted that the pipe 0 is free from bends or the like which might cause stock to lodge therein below the level of the feed spout where the valve 12 is'situated, so that should the air flow fail due to fan failure, the stock will drop out of the pipe 0; therefore on restoration of the 'air flow, there will not be any blocks in the system which will have to be cleared before normal operation recommences.

Instead of the elevating pipe 0 being connected to the cyclone h by aright angle bend as in 'Figur'e'l, it may be so connected by a bend of relatively slight curvature as shown in Figure 2 so as not to unduly retard the flow through the bend.

The'cyclone h may as shown in Figure 3 have its axis" slightly inclined to the horizontal; or it may be horizontal in order to eliminate the 'bend in the connection from the pipe 0 to the cyclone.

There may be an expansion box at '0 between the top of the elevating pipe c and the cyclone h. This is shown in Figure 4. This eliminates the possibility ofstock accumulating in the horizontal pipe forming the inlet to the cyclone and causing chokes. The material discharged through the rotary seal 0 below the expansion box 0 may be caused to join that discharged from the cyclone through the rotary seal is through pipe is.

' In the stock elevating and machine exhaustion system shown in Figures 5 and 6, the elevating pipes 0 pass through the machine a which is shown as a roller mill. The doors a," provide air inlets and the pipes 0 each have an aperture p therein controlled by slides q through which stock, with air exhausted from the machine, pass into the elevating pipes. The interior 'of the base of the machine is inclined and arranged as hoppers as shown to guide the stockinto the apertures p. The elevating system is otherwise the same or similar to what is shown in Figure 1.

In the modification shown in Figure 7, the air which is drawn into the feed spout I) along with the stock separates from the latter at r "and passes separately into the elevating pipe 0 ing pipe 0.

to discharge from the base of the pipe 0 should 4 by the branch s which may have a control valve 1? thereon. The flow of mill stock into the elevating pipe is through the rotary seal u which will be turned at a controlled rate. The elevating pipe is enlarged at v where the air enters from the branch s.

In Figure 8, the flow of mill stock from the machine a into the downwardly inclined feed spout b is through a conveyor w revolved by suitable means. The exhaustion air from the machine separates from the stock and enters the elevating pipe 0 by the branch 5' as in Figure 7.

Figure 9 is similar to Figure 7, but the rotary seal in the feed spout b is omitted.

In the Figure 10 arrangement, the air which separates from the stock in the feed spout b is taken by a separate pipe :1: to a point in the elevating pipe below the discharge mouth of the feed spout b and assists in elevating the stock entering the pipe 0 from the feed spout.

' In the Figure 11 arrangement, the air separated from the stock, which is as in Figure 10, delivered into the elevating pipe 0 by the pipe 0: below the discharge mouth of the feed spout lb, constitutes the only air for elevating the stock, there being a normally closed connection between the pipe 1:, and the base of the'elevat- In order, however, to allow stock the suction fail due to the fan 9, Figure 1, going out of action, a hinged flap y is provided on the lower side of the bend at the base of the pipe 0. This flap is held closed by the suction during normal working but opens, if the suction fails, due to the pressure of the stock which accumulates in the base of the pipe 0. The flap is suitably counterweighted to maintain it normally closed.

In the Figure 12 arrangement, air is admitted to the bottom of the elevating pipe as in Figure 10, but no rotary seal is fitted in the pipe b.

Figure 13 shows several machines being exhausted from one pneumatic elevating pipe 0. There. is a sieving machine 2 on the top floor, a plansifter 3 on the middlefloor and a roller mill on the bottom floor. Each machine i ex- .hausted to the feed spout b. The air exhausted from the sieving machine and plansifter does not contain the stock dealt with by such machines but is used to assist in the elevation of the stock from the roller mill. the stock enters the elevating pipe 0 by the branch s. There is a rotary seal at u in the feed spout as in previous figures.

By the aforesaid arrangements not only is it possible to reduce the resistance of the system in some cases to about half that customary in known" pneumatic elevating systems but also to reduce the air quantity in some cases down to about so that the power required is reduced to about a third. Furthermore, if for any reason the air supply to the elevator fails, the stock delivered into the vertical pipe is discharged through the open bottom of the latter is in contact with the air, it is cooled to within a few degrees of the temperature of the ele- Air which separates from I aeeasca vator, thus rendering:- the stock: in good condition for; si fting. It is foundalso that infesta tion oi the-stockis eliminated due to the high v locity air stream which prevents breeding of the insects. It istherefore clear that. the pres-. ent; invention provides a pneumatic conveying system forhandling" flour stocks for use in a flour mill, the system. comprising conduit means.

that providea downwardly extending gravita-.. tion-aliy influenced inlet that receives processed stock andair to.- be conveyed. In the specific form illustrated in Figure 13, this inlet furtherreceivesexhaust air from other stock treating apparatus such as a sieving machine 2 and the plansifter 3:. This exhaust air of these: ma chines assists in the elevation. of processed; stools flowing into the inlet from the roller mill 4, A vertically disposed elevating conduit is; pros vided and. the. gravitationallyinfluenced. inlet: communicates with this: conduit; current. indue ing means communicate with the elevating conduit and are operative to establish an air current that conveys stock and airdownward through the gravitationally influenced inlet and upwardly through the elevating conduit. Spercifically the. air current inducing means constirtutes a fan connected to the outlet of a separator, usually a cyclone: separator. A by-pass conduit. is; provided that communicates betweenthe downwardly extending inlet and the vertical conduit, the. latter point. of communication be ing; in axial spaced. relation with respect to the juncture. of the downwardly extending or inclined. inlet and the vertical conduit; Air is, separated from processed stock and passes through this. by-passconduit. and into the, elevatingconduit independently ofthe stock. From a specific standpoint, as applied to some of, the modifications disclosed, the elevating; conduit terminates in. an open lower end beneath, the juncture of'the inlet therewith. Thisopen lower end includes. a mo able. por i n: and means m n in the same f a u tin mo em n o that the; cross..-sectional area; of: this lower end; a e va i d in: rd r o; regu ate; air nowin he. system...

What I claim; is:

1.. .31 ombin ..:ion with a mill; for; rind n mill stocks includ naerindins; el ments ndim et means-i911 stock-and air, a substanti lly rt' QaL e ev ti p pe, mea sv prov din mm n cation; between. h mi l and; the pe: s that ground stoclgcan flow into the; pipe, said ele, spine. in udin an pp d, air cur nt. s eans mm n cati w th. the up r end saidpipe; for exhausting said mill and sjmulta eouslyelevating ground, stock through aid; n n S nd iper exte d ng; t rough. said. mill and terminating therebeneathin an Open lower, and sad. ill, hav g: ean efi n a hop shaped enclosure including an; inclined; bottom, and said pipe having an opening therein adjacent the; inclined; bottom and communicating therewith and through which opening ground stock ficwscintpithe pipe.

A p eumati i pnr vma yst m orv andl n flour stocks for use in a flour mill comprising a substantially vertically extending elevator con. duit, said. conduit having. uppen and lower ends andthe. lower end being. open, conduit means-prov di g; d wnwardly exte dina a itatio a y influenc d? nletior. receiv roce d toc a air; abeqonv ve aidcon uit a s co u cating with the elevator conduit above the lower end r del eringznro cs edstocls d ect n Said vertical conduit, air current inducing means com- 6 municating with theupper end: of said elevating conduit for simultaneouslydraw-ing a current ofi air and processed stockdownwardly through the conduit means, and into the said elevator con-.- duit to providea lifting currentto elevate stock vertically: upward through said elevator conduit,- andthrottle means embodied with the IOWEFBnd. of said elevator conduit below the juncture of. said inlet therewith to vary the cross-sectional area, thereof and thereby the flow of air there int);

3 A pneumatic conveying system ior-handl'ing, flour stocksfor usea flour mill comprising; a. substantially vertically extending elevator conduit, said conduit having upper and lower endsv andthelower end being open, conduit means pro.-.. vi'd-ing a downwardly extending gravitationally influenced inlet for receiving processed stool-1' and air to -be conveyed, said inlet communicatingwith: theeievator conduit abovethe lower-end for de.-. livering processed stock directly to saide-levaton conduit, air current inducing means com-mums. eating with the upper-wand of said elevator-con duit for simultaneously drawing a current ofain through the inlet and into the lower end oi said elevator conduit to convey: stock and air, downwardly through said conduit means; into: said elevator conduit and to provide alifting, current to elevate-stock vertically: through said elevator conduit, throttle means embodied with the lower endof said elevator conduit below the juncture of said inlet therewith-to vary-the crosssectional" area thereof and thereby the flow: of air thereinto, and means controlling communi .2 cation between said elevatonconduit and said= ins let to cooperate with said throttle means toregulate the ratio of elevating-air to' the air drawn. into said elevator conduit along" with. thepro' cessed stock coming-from the mill;

4. The combination as defined in and by-claim 3* and a cyclone separator having tangentiallyarranged inletand outlet means; said air cure rent inducing means communicating with said: outlet means and said inlet means: substantially directly communicating with the upper-end of said vertical conduit;

5.; The combinationas clefined in and by claim- 4 andin which said cyclone-separator isdisposed with its axis at least substantiallyhorizontali 6.- A- pneumatic conveying system for handling fiounstocks comprising, in' combination, afirst machine for'treating-stock, means com rising: a separating apparatus located above said -first" ma:.- chine-and including an inlet andan outlet; axf'anconnectedto said outlet to withdraw air therefrom; asubstantia-lly vertical conduit connected. to the' inletof said'separatingapparatus and ex tending below said first machine, a conduitconenected to the outletof said first machineand extending downwardly-to connect-with said-"vertical conduit at a junction-bolowsaidfirst -machine toprovide a gravity feed therefrom= to said vertical conduit, additional stock treating appa, ratus-locatedabovesaid first machine, and meansforming air-- exhaust connections: between. said additional stock treating apparatus and said lasta mentioned conduit. whereby said fan aided by gravityinduces the fiow of 'stock' and air from said-'first'machinathrough said conduits to said separatingapparatus and continuously exhausts air from; said machine-and said apparatus;

I The combination-as defined inand-by claim 6';in which there is a pipe connectedjto said lastmentioned conduit at a point intermediate its ends andin turn connected'to said'verticalcom 7 duit at a point above said junction so that air from said machine and said apparatus may separate from stock in said last mentioned conduit and may by-pass said junction.

8. The combination as defined ,in and by claim 6 in which the additional stock treating apparatus comprise a plansifter and a sieving machine located one above the other.

9. A pneumatic conveying system comprising, in combination, a milling machine for treating stock, means comprising a separating apparatus located above said milling machine and including an inlet and an outlet, a fan connected to saidoutlet to withdraw air therefrom, a substantially vertical conduit connected to the inlet of said separating apparatus and extending below said millingmachine, a second conduit connected to the outlet of said milling machine and extending downwardly to connect with said vertical conduit at a junction below said milling machine to provide a ravity feed from said milling machine to said vertical conduit for the flow of stock and vair, additional stock treating apparatus located above said milling machine, a pipe connected to said last-mentioned conduit at a point intermediate its ends. and in turn connected to said vertical conduit at a point above saidjunction, air exhaust conduit means connected between said additional stocl; treating apparatus and said second conduit and communicating with the latter at an area rearwardly of the point of communication of said pipe with said second conduit so that air is exhausted in said additional apparatus and assists the conveying of stock, and a rotary seal located in said secondmentioned conduit between said pipe and said junction so that air separates from the stock in said second conduit and by-passes said junction.

10. Pneumatic conveying system for handling flour stocks for use in a flour mill comprising conduit means providing a downwardly extending gravitationally influenced inlet for receiving processed stock and air to be conveyed, a vertically disposed elevating conduit, said inlet com.- municating with said conduit, air current inducing means communicating with said conduit and operative to establish an air current to convey stock and air downward through said conduit means and upward through said elevating conduit and a by-pass conduit communicating at one end with said conduit means and at its other end with said elevating conduit at a point in axial spaced relation with respect to the juncture of said conduit means and said elevating conduit so that air may be separated from the stock passing through said conduit means and passed into said elevating conduit independently of the stock.

11. A conveying system as defined in and by claim 10 in which the elevating conduit terminates in an open lower end beneath the juncture of the inlet therewith, including a movable portion and means mounting the same for adjusting movement to vary the cross-sectional area of said lower end for regulating air in-flow into the system.

12. Pneumatic conveying system for handling flour stocks for use in a flour mill comprising conduit means providing a downwardly extending gravitationally influenced inlet for receiving processed stock and air to be conveyed, means providing a separating zone above said inlet and including an inlet for stock and air, a stock outlet and an air outlet, a vertically disposed elevatin conduit communicating at one end with the inlet of said separating zone and having a yertical extent sufficient to dispose its other end beneath said conduit means, said conduit means communicating with said elevating conduit at an area spaced from the lower terminus of the vertical extent of the elevating conduit, air current inducing means communicating with the air outlet of the separating zone and operative to establish an air current to convey stock and air downward through said conduit means and upward through said elevating conduit, and a by-pass conduit communicating at one. end with said conduit means and at its other end with said elevating conduit at a point in axial spaced relation with respect to the juncture of said con} duit means and said elevating conduit so that, air may be separated from the stock passing through said conduit means and passed into said elevating conduit independently of the stock.

13. The combination as defined in and by claim 12 in which the separating zone is constituted by a cyclone separator including means providing a large expansionchamber and said separator having a substantially vertical inlet leading to said chamber and said elevating con-: duit communicating directly with said vertical inlet.

14. A conveying system as defined in and by. claim 12 in which the elevating conduit termi: nates in an-open lower end beneath the uncture of the inlet therewith, including a movable portion and means mounting the same for adjusting movement to vary the cross-sectional area of said lower end for regulating air in-flow into the system.

15. A pneumatic conveying system as defined in and by claim 12 in which a mechanical conveyor is arranged in advance of said downwardly extending gravitationally influenced inlet.

16. A conveying system as defined in and by claim 12 in which said by-pass conduit commu nicates with the elevating pipe above the point of communication of the downwardly extending gravitationally influenced inlet therewith.

17. A conveying system as defined in and by claim 12 in which said by-pass conduit communicates with the elevating pipe below the point of communication of the downwardly gravitationally influenced inlet therewith. I

18. A conveying system as defined in and by claim 17 in which said branch conduit separates air flowing from said stock through said inlet and delivers the air to the vertically disposed elevating conduit beneath the point of entrance of stock thereinto so that the separated air constitutes the elevating air and said vertical conduit including means providing a normally closed opening therein subjacent the point of entrance of stock thereinto, said means including a flap opening upon cessation of suction to permit egress of stock therethrough.

I GEORGE WATTS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 79,044 Wood June 16, 1868 297,757 Case A r. 29, 1884 297,890 Welch Apr. 29, 1884 620,270 Bradford Feb. 28, 1899 881,296 Bridden et al Mar. 10, 1908 (Other references on following page) 9 10 UNITED STATES PATENTS FOREIGN PATENTS Number Name Date Number Country Date 1 g eyi 356,794 Great Britain Sept. 7, 1931 em t 5 231,487 Switzerland July 4, 1950 1,449,169 Elzemeyer Mar. 20, 1923 1,585,876 Quadef May 25, 1926 OTHER REFERENCES 178971144 Pmuty 1933 American Miller and Processor, June 1946. 1,912,910 Neuman et June 1933 Article entitled Pneumatics by H. K. Ferguson, 2,041,188 JOhnSOH May 1936 0 pages 33-40, 42, 46, s2, s5 and 87.

2,513,370 Shaw July 4, 1950 1 

